What does the cryptic crossword clue "Back up signs possibly for shift in responsibility? (4,7)" mean?

The wordplay uses an anagram. anagram of BACK + UP + SIGNS = BUCKPASSING The answer is BUCKPASSING.

Back up signs possibly for shift in responsibility? (4,7)

Daily Mail Cryptic #17246 | 12 Across | 2023-12-08 flower